From http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf,
section 6.2.17 _CCA states that ARM platforms require ACPI _CCA object to be specified for DMA-cabpable devices. Therefore, this patch specifies ACPI_CCA_REQUIRED in arm64 Kconfig.
In addition, to handle the case when _CCA is missing, arm64 would assign dummy_dma_ops to disable DMA capability of the device.
Acked-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Mark Salter msalter@redhat.com Signed-off-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/dma-mapping.h | 18 ++++++- arch/arm64/mm/dma-mapping.c | 92 ++++++++++++++++++++++++++++++++++++ 3 files changed, 109 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 4269dba..95307b4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1,5 +1,6 @@ config ARM64 def_bool y + select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI select ACPI_REDUCED_HARDWARE_ONLY if ACPI select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h index 9437e3d..f0d6d0b 100644 --- a/arch/arm64/include/asm/dma-mapping.h +++ b/arch/arm64/include/asm/dma-mapping.h @@ -18,6 +18,7 @@
#ifdef __KERNEL__
+#include <linux/acpi.h> #include <linux/types.h> #include <linux/vmalloc.h>
@@ -28,13 +29,23 @@
#define DMA_ERROR_CODE (~(dma_addr_t)0) extern struct dma_map_ops *dma_ops; +extern struct dma_map_ops dummy_dma_ops;
static inline struct dma_map_ops *__generic_dma_ops(struct device *dev) { - if (unlikely(!dev) || !dev->archdata.dma_ops) + if (unlikely(!dev)) return dma_ops; - else + else if (dev->archdata.dma_ops) return dev->archdata.dma_ops; + else if (acpi_disabled) + return dma_ops; + + /* + * When ACPI is enabled, if arch_set_dma_ops is not called, + * we will disable device DMA capability by setting it + * to dummy_dma_ops. + */ + return &dummy_dma_ops; }
static inline struct dma_map_ops *get_dma_ops(struct device *dev) @@ -48,6 +59,9 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev) static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, struct iommu_ops *iommu, bool coherent) { + if (!acpi_disabled && !dev->archdata.dma_ops) + dev->archdata.dma_ops = dma_ops; + dev->archdata.dma_coherent = coherent; } #define arch_setup_dma_ops arch_setup_dma_ops diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index ef7d112..6e6d6ad 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -415,6 +415,98 @@ out: return -ENOMEM; }
+/******************************************** + * The following APIs are for dummy DMA ops * + ********************************************/ + +static void *__dummy_alloc(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t flags, + struct dma_attrs *attrs) +{ + return NULL; +} + +static void __dummy_free(struct device *dev, size_t size, + void *vaddr, dma_addr_t dma_handle, + struct dma_attrs *attrs) +{ +} + +static int __dummy_mmap(struct device *dev, + struct vm_area_struct *vma, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + struct dma_attrs *attrs) +{ + return -ENXIO; +} + +static dma_addr_t __dummy_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + return DMA_ERROR_CODE; +} + +static void __dummy_unmap_page(struct device *dev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + struct dma_attrs *attrs) +{ +} + +static int __dummy_map_sg(struct device *dev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + return 0; +} + +static void __dummy_unmap_sg(struct device *dev, + struct scatterlist *sgl, int nelems, + enum dma_data_direction dir, + struct dma_attrs *attrs) +{ +} + +static void __dummy_sync_single(struct device *dev, + dma_addr_t dev_addr, size_t size, + enum dma_data_direction dir) +{ +} + +static void __dummy_sync_sg(struct device *dev, + struct scatterlist *sgl, int nelems, + enum dma_data_direction dir) +{ +} + +static int __dummy_mapping_error(struct device *hwdev, dma_addr_t dma_addr) +{ + return 1; +} + +static int __dummy_dma_supported(struct device *hwdev, u64 mask) +{ + return 0; +} + +struct dma_map_ops dummy_dma_ops = { + .alloc = __dummy_alloc, + .free = __dummy_free, + .mmap = __dummy_mmap, + .map_page = __dummy_map_page, + .unmap_page = __dummy_unmap_page, + .map_sg = __dummy_map_sg, + .unmap_sg = __dummy_unmap_sg, + .sync_single_for_cpu = __dummy_sync_single, + .sync_single_for_device = __dummy_sync_single, + .sync_sg_for_cpu = __dummy_sync_sg, + .sync_sg_for_device = __dummy_sync_sg, + .mapping_error = __dummy_mapping_error, + .dma_supported = __dummy_dma_supported, +}; +EXPORT_SYMBOL(dummy_dma_ops); + static int __init arm64_dma_init(void) { int ret;